The present invention relates to the field of techniques for the process of photolithography mask writing.
Usually photomask data preparation and photomask writing is done in two steps:
(1) Fracture a decorated layout into simpler shapes such as rectangles and trapezoids; and
(2) Correct for mask process effects: (a) Correction for proximity effects correction (PEC) (dose adjustment and/or biasing); (b) correction for mask making process; and (c) correction for mask etching process.
Both laser and electron beam lithography (i.e., e-beam lithography) fixed diameter mask writers have been in production for many years. Electron beam lithography is the practice of emitting a beam of electrons in a patterned fashion across a surface covered with a film, called the resist, and selectively removing either exposed or non-exposed regions of the resist, called developing. Edge-based real-time dose correction hardware/software systems have been used previously.
The primary electrons in the incident beam lose energy upon entering a material through inelastic scattering or collisions with other electrons.
Therefore, what is needed is an improved technique for preparing data for writing photomasks, especially for data path handling, shot count minimization, and proximity effects correction.